A common technique of making spring mattresses is the so-called pocket technique. This means that the springs are enclosed in pockets, i.e. they are individually enclosed by a casing material. In this way, the springs will be relatively individually resilient so that they can flex individually without affecting the neighboring springs and, thus, the comfort for the user increases since his weight will be distributed more uniformly over the surface that receives the load.
A drawback of such mattresses is, however, that they are significantly more expensive to manufacture than many other types of spring mattresses, and since a considerable amount of casing fabric is required to enclose each spring individually. It is therefore desirable, without lowering the mattress's standards of quality, to reduce the amount of fabric. Additionally, the fabric of which the pocket casings can be made, can vary in quality and consequently vary in cost. However, if fabrics of lower quality are used, a rustling noise is known to arise as the casing along with the spring is flexed under load. The rustling can be audible to the user of the mattress, causing him discomfort, and consequently, more expensive fabrics are preferred and are therefore adding to the overall cost. Thus, to be able to use a less expensive casing fabric, there is a need for eliminating or diminishing the rustling problem during ordinary use of the mattress.
Taken together, there is a need for a mattress which is easier and/or less expensive to manufacture but which at the same time provides at least an equivalent comfort compared with other prior-art pocket mattresses. The drawbacks are partly eliminated by the mattress disclosed in WO 02/44077 by the same applicant. This mattress comprises strings, in which the springs are more separated than has been known so far. This has been found not only economically advantageous, but the mattress has also been found to be comfortable to the same extent as prior-art mattresses. However, in this solution it is still difficult to obtain the desired individual resilience of the individual springs. Additionally, the attempt to benefit from less expensive casing fabrics remains as well as the attempt to reduce the considerable amount of casing fabrics required to enclose each spring individually. It is therefore still a need for a more cost effective and/or more comfortable mattress.